MLV vaccines to reduce seminal shedding of type 1 PRRSv

Transbound Emerg Dis. 2017 Feb;64(1):194-203. doi: 10.1111/tbed.12361. Epub 2015 Apr 16.

Two Commercial Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)-ModifiedLive Vaccines Reduce Seminal Shedding of Type 1 PRRSV but not Type 2 PRRSV in InfectedBoars.

Park C1, Kim T1, Choi K1, Jeong J1, Kang I1, Park SJ1, Chae C1.

Author information

1

Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, Seoul, Korea.

Abstract

The objective of this study was to compare the effects of two commercial type 1 porcine reproductive and respiratory syndrome virus(PRRSV)-modified live vaccines on type 1 and type 2 PRRSV shedding in the semen of experimentally infected boars. Upon challenge with PRRSV, unvaccinated boars exhibited an increase in daily rectal temperature (39.4-39.7°C). Vaccination of boars with type 1PRRSV significantly reduced the amount of type 1 PRRSV load in blood and semen after challenge with type 1 PRRSV, but barely reduced the amount of type 2 PRRSV load in blood and semen after the type 2 PRRSV challenge. There were no significant differences in the reduction of viremia and seminal shedding of type 1 and type 2 PRRSV between the two commercial vaccines. The seminalshedding of PRRSV is independent of viremia. The reduction of type 1 PRRSV seminal shedding coincided with the appearance of type1 PRRSV-specific interferon-γ secreting cells (IFN-γ-SC) in vaccinated type 1 PRRSV-challenged boars. The frequencies of type 1PRRSV-specific IFN-γ-SC induced by type 1 PRRSV vaccine are relatively high compared to type 2 PRRSV-specific IFN-γ-SC induced by the same vaccine which may explain why type 1 PRRSV vaccine is more effective in reducing seminal shedding of type 1 PRRSVwhen compared to type 2 PRRSV in vaccinated challenged boars. These results provide clinical information on how to reduce seminalshedding of type 1 PRRSV in boars using type 1 PRRSV-modified live vaccine.

© 2015 Blackwell Verlag GmbH.

KEYWORDS: 

boar; cross-protection; porcine reproductive and respiratory syndrome virus; semen; vaccine

PMID:

 

25879825

 

DOI:

 

10.1111/tbed.12361